1. Field of the Invention
The present invention is directed to an oil sump for use in internal combustion engines or transmissions and particularly an oil sump made of sheet metal having a reinforced peripheral area for mounting the same to the combustion engine or transmission.
2. Description of the Related Art
Internal combustion engines, both those built into motor vehicles and those operated on a stationary basis, usually have an oil sump, which is installed in the crankcase near the crankshaft and encloses the crankshaft. Oil sumps of this type are also used in transmissions. It is also customary to provide sump covers for such oil sumps for purposes of sound insulation. Sump covers of this type are often produced from steel sheet, which is formed into a cover by the deep-drawing process.
Oil sumps of this type are subjected to very large forces of acceleration due to the vibrations of the internal combustion engine or of the motor vehicle if the internal combustion engine is being operated in a motor vehicle. For example, accelerations of up to 50 times the acceleration of gravity have been measured in oil sumps of commercial vehicles. As a result, special design measures must be taken, especially in the area of the mounting of the sump to the internal combustion engine, to prevent cracking in this area of the sumps and to guarantee reliable sealing from the crankcase. The same applies to oil sumps in transmissions.
In this connection, DE 88 01 471 U1 discloses the provision of reinforcing seams on the edge of the sump bent in the form a flange, where the through holes for mounting bolts for mounting the oil sump to the crankcase are located between the peripheral reinforcing seams, and the oil sump is mounted to the crankcase with a seal placed between them. One disadvantage of this arrangement is that the mounting bolts, which make point contact, are conducive to crack formation, so that sufficiently strong vibrations of the oil sump lead to cracking. Another disadvantage is that the mounting bolts, which make point contact, cause deflection of the flange between the mounting points due to the elasticity of the material, so that the oil sump is pressed against the crankcase with highly variable forces over the length of the flange.
In addition, DE 39 29 592 A1 discloses the mounting of a deep-drawn sheet-metal oil sump by bolts on a flange of the crankcase with the interposition of a shaped intermediate piece or bridge in order to increase the flexural strength of the oil sump flange. The problem with this arrangement is that, due to the relatively high manufacturing tolerances that occur in the deep drawing of the oil sump, shaped bridges have very large dimensional deviations from the oil sump, if they are to stiffen the entire peripheral flange of the oil sump, i.e., are manufactured as a single piece or in several relatively long sections. On the one hand, this causes big problems with respect to mounting, and, on the other hand, there is an uneven distribution of the contact forces of the shaped bridge on the flange and, consequently, an increased tendency to cracking in the areas of the oil sump that are acted upon by higher contact pressure. Moreover, uneven contact of the flange of the oil sump on the crankcase flange can have a negative effect on the seal between them.
Finally, it is known from DE 34 27 529 A1 (U.S. Pat. No. 4,619,343) that the oil sump and the crankcase can be joined by means of spring clips.